Heat exchanger

ABSTRACT

A heat exchanger includes a tank, multiple tubes, a tube support member that supports the multiple tubes, and a shell body joined to the tube support member. The tube support member is cylindrical and includes a first-end cylindrical portion, a second-end cylindrical portion, and an intermediate cylindrical portion having a diameter smaller than that of the first-end cylindrical portion and having a predetermined length in an axial direction between the first-end cylindrical portion and the second-end cylindrical portion. The tank and the first-end cylindrical portion are welded to each other. The shell body and the second-end cylindrical portion are brazed to each other. Outer peripheral portions of the tubes are in contact with and brazed to an inner surface of the intermediate cylindrical portion.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of International Patent Application No. PCT/JP2018/024344 filed on Jun. 27, 2018, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2017-153985 filed on Aug. 9, 2017. The entire disclosures of all of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger.

BACKGROUND

A heat exchanger includes a heat barrier between a body of the heat exchanger and a casing housing a catalyst converter such that an influence of heat generated at the time of welding of the body and the casing is reduced.

SUMMARY

According to at least one embodiment of the present disclosure, a heat exchanger includes a tank into or from which a first fluid flows, a plurality of tubes through which the first fluid flows, a tube support member which is joined to and supports the plurality of tubes and joined to the tank, and a shell body which accommodates therein the plurality of tubes such that a second fluid flows around the tubes. The shell body is joined to the tube support member. The tube support member is a cylindrical body extending in an alignment direction along which the tank and the shell body are aligned. The tube support member includes a first-end cylindrical portion provided on a first end part of the cylindrical body in an axial direction, a second-end cylindrical portion provided on a second end part of the cylindrical body in the axial direction, and an intermediate cylindrical portion which is smaller in diameter than the first-end cylindrical portion and is between the first-end cylindrical portion and the second-end cylindrical portion. The intermediate cylindrical portion has a predetermined length in the axial direction. The tank and the first-end cylindrical portion are welded to each other. The shell body and the second-end cylindrical portion are brazed to each other. Outer peripheral portions of the plurality of tubes are in contact with and brazed to an inner surface of the intermediate cylindrical portion such that the tube support member supports the outer peripheral portions of the plurality of tubes. A brazed joint between the shell body and the second-end cylindrical portion is located inward in the axial direction more than brazed joints between the outer peripheral portions of the plurality of tubes and the intermediate cylindrical portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a schematic configuration of an exhaust gas cooler according to at least one embodiment.

FIG. 2 is a partial cross-sectional view showing a configuration relating to joining of a tube, a tube support member, a shell body, and a tank in an exhaust gas cooler.

FIG. 3 is a partially enlarged view showing a joint between the tank and the tube support member, a joint between the tube and the tube support member, and a joint between the tube support member and the shell body, according to at least one embodiment.

FIG. 4 is an enlarged view showing joints of respective parts according to a comparative example.

FIG. 5 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 6 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 7 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 8 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 9 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 10 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 11 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

FIG. 12 is a partially enlarged view showing a joint between a tank and a tube support member, a joint between a tube and the tube support member, and a joint between the tube support member and a shell body, according to at least one embodiment.

DETAILED DESCRIPTION

A comparative example will be described. A heat exchanger of the comparative example includes a heat barrier part by interposing an adapter ring between a shell body and a casing containing when the shell body and the casing are joined to each other by welding. Heat generated during the welding can be cooled before reaching a brazed part between the shell body and a tube sheet or a brazed part between the tube sheet and a tube. In other words, the heat can be reduced to a degree that a thermal influence such as thermal distortion is almost negligible.

According to the heat exchanger of the comparative example, the tube sheet has a shape extending only outward of the heat exchanger more than the brazed joint with the tube. Thus, the brazed joint between the shell body and the tube sheet is located outward of the heat exchanger in the axial direction more than the brazed joint between the tube and the tube sheet. Accordingly, in the heat exchanger of the comparative example, the dimension in the axial direction may become long in order to reduce the thermal influence such as thermal distortion at the brazed part.

In contrast, according to an aspect of the present disclosure, a heat exchanger includes a tank into or from which a first fluid flows, a plurality of tubes through which the first fluid flows, a tube support member which is joined to and supports the plurality of tubes and joined to the tank, and a shell body which accommodates therein the plurality of tubes such that a second fluid flows around the tubes. The shell body is joined to the tube support member. The tube support member is a cylindrical body extending in an alignment direction along which the tank and the shell body are aligned. The tube support member includes a first-end cylindrical portion provided on a first end part of the cylindrical body in an axial direction, a second-end cylindrical portion provided on a second end part of the cylindrical body in the axial direction, and an intermediate cylindrical portion which is smaller in diameter than the first-end cylindrical portion and is between the first-end cylindrical portion and the second-end cylindrical portion. The intermediate cylindrical portion has a predetermined length in the axial direction. The tank and the first-end cylindrical portion are welded to each other. The shell body and the second-end cylindrical portion are brazed to each other. Outer peripheral portions of the plurality of tubes are in contact with and brazed to an inner surface of the intermediate cylindrical portion such that the tube support member supports the outer peripheral portions of the plurality of tubes. A brazed joint between the shell body and the second-end cylindrical portion is located inward in the axial direction more than brazed joints between the outer peripheral portions of the plurality of tubes and the intermediate cylindrical portion.

According to the above configuration, the shell body is brazed to the tube support member and the brazed joint is located inward in the axial direction more than the brazed joints between the tubes and the tube support member. In other words, the brazed joint between the shell body and the tube support member is near to the second end. Therefore, a heat exchanger reduced in its axial length can be provided. Further, since the intermediate cylindrical portion has a diameter smaller than that of the first-end cylindrical portion welded to the tank, a heat transfer distance between the welded joint and the brazed joint can be secured. In addition, since the brazed joint between the shell body and the second-end cylindrical portion is separated from the welded joint by the intermediate cylindrical portion, the strength can be secured. According to the above configuration, the heat exchanger can reduce the thermal influence caused by welding of the tank and the tube support member, and the axial length of the heat exchanger can be reduced.

Hereinafter, multiple embodiments for implementing the present disclosure will be described referring to drawings. In the respective embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

A heat exchanger according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 4. The heat exchanger is a device for exchanging a heat between a first fluid flowing inside tubes 30 and a second fluid flowing around the tubes 30. An exhaust heat exchange device described in the first embodiment is an example of a heat exchanger according to the present disclosure. The exhaust heat exchange device is applied to an EGR cooler 1 (also referred to as an exhaust gas cooler 1) in an exhaust gas recirculation device (EGR device) such as a diesel engine for a vehicle or a gasoline engine which is an example of an internal combustion engine.

The EGR cooler 1 is an exhaust heat exchange device that cools an exhaust gas (an example of a first fluid) recirculated to an intake side of the engine by coolant water (an example of a second fluid) as a cooling fluid for cooling the engine. As shown in FIGS. 1 and 2, the EGR cooler 1 includes a heat exchanging core portion including multiple tubes 30, a tank 4, a tank 5, a shell body 2, a water inflow pipe 20, a water outflow pipe 21, and the like inside. Each of the members is made of, for example, an aluminum material, an aluminum alloy material, a stainless steel material, or the like which is light in weight and excellent in thermal conductivity, and the contact parts of each member are joined to each other by brazing or welding. Each of the members is coated with a brazing material. The brazing material clad to the respective members by an in-furnace brazing process or the like is melted to join the members in a joining relationship to each other. As each of the members, a member to which a paste-like brazing material is applied or a plate material to which a brazing material is applied can be used.

The tank 4 is an exhaust gas inflow portion on the upstream side into which the exhaust gas from the exhaust pipe flows. The tank 4 is provided with a flange portion 41 connected to an exhaust pipe at an upstream end, and an inflow port 40 opened inside the flange portion 41 in the upstream-side end portion. A downstream-side end portion of the tank 4 is connected to a tube support member 6. The tank 5 is a downstream side exhaust gas outflow portion that collects the exhaust gas flowing out of each tube 30 and causes the exhaust gas to flow out into a pipe connected to the intake side of the engine. The tank 5 is provided with a flange portion 51 connected to a pipe at a downstream end, and an outflow port 50 opened inside the flange portion 51 in the downstream-side end portion. The upstream-side end portion of the tank 5 is connected to a tube support member 6.

The heat exchange core includes the multiple tubes 30 inside which an exhaust gas discharged from the engine flows. The shell body 2 accommodates the multiple tubes 30 inside. The shell body 2 is provided with a water inflow pipe 20 into which a coolant water flows and a water outflow pipe 21 through which the coolant water flows out. The coolant water flows around the multiple tubes 30 inside the shell body 2. A water passage 2 a through which the coolant water flows is provided around the multiple tubes 30 surrounded by the shell body 2.

The tubes 30 are tube members through which an exhaust gas as a first fluid flows, and are each configured, for example, by joining two tube plates. Each of the tube plates is formed into a U-shape having a shallow cross section from a flat plate by press working or roll working. The open sides of the tube plates are joined to each other, so that the tube 30 is configured as an elongated tube member having a flat rectangular shape in a cross section intersecting with a longitudinal direction of the tube 30. Rectangular openings are provided at both ends of each tube 30 in the longitudinal direction. An inner fin may be provided inside each tube 30.

The multiple tubes 30 configure a tube assembly 3 in which main surfaces of the tubes on a long side of a flat rectangular cross-section are stacked so as to face each other. The tube assembly 3 is a tube group in which the multiple tubes 30 are integrally stacked on each other in a state in which the adjacent tubes 30 are in contact with each other. The multiple tubes 30 configuring the tube assembly 3 are brazed and joined to each other in a state in which the adjacent tubes 30 are in contact with each other at both end portions in the longitudinal direction. As shown in FIG. 2, the surfaces of the adjacent tubes 30 are separated from each other in parts other than the both end portions of the tube assembly 3. Multiple projection and recess portions may be provided on the main surface of the tube 30 as a temperature decrease means for lowering a temperature of a temperature boundary layer of the coolant water on an outer surface of the tube 30. In addition, the parts of the tube assembly 3 excluding both end portions of the tube assembly 3 may be in a form in which the surfaces of the adjacent tubes 30 are in contact with each other.

The tube support members 6 are cylindrical bodies that are provided one by one at both end portions of the multiple tubes 30 in the longitudinal direction so as to support the tubes 30. The tube support members 6 are cylindrical bodies whose alignment direction is an axial direction in which the tank 4 or the tank 5 and the tube assembly 3 are aligned side by side. One of the tube support members 6 supports the tube assembly 3 and is joined to the tank 4 and the shell body 2 on the upstream side of an exhaust gas flow in the EGR cooler 1. The other tube support member 6 supports the tube assembly 3 and is joined to the tank 5 and the shell body 2 on the downstream side of the exhaust gas flow in the EGR cooler 1. One tube support member 6 located at the upstream side of the exhaust gas flow functions as a member for separating an inner space of the tank 4 and an internal space of the shell body 2 from each other, and the tube support member 6 separates the exhaust gas passage and the water passage 2 a in the tank 4 from each other in a blocking manner. The other tube support member 6 located at the downstream side of the exhaust gas flow functions as a member for separating an internal space of the shell body 2 and an inner space of the tank 5 from each other, and the tube support member 6 separates the water passage 2 a and the exhaust gas passage in the tank 5 from each other in a blocking manner.

A configuration of the tube support members 6 will be described with reference to FIG. 3. The tube support member 6 includes an intermediate cylindrical portion 62 having an inner diameter size in which a longitudinal end portion of the tube assembly 3 can be fitted. The tube support member 6 includes a first-end cylindrical portion 60 joined to the tank 4 on a first side of the cylindrical body in the axial direction. The tube support member 6 includes a second-end cylindrical portion 61 joined to the shell body 2 on a second side of the cylindrical body in the axial direction. The first side in the axial direction is also axially outward of the EGR cooler 1 (heat exchanger). The second side in the axial direction is also axially inward of the EGR cooler 1 (heat exchanger). The second-end cylindrical portion 61 has a diameter smaller than that of the first-end cylindrical portion 60. The intermediate cylindrical portion 62 is a portion smaller in diameter than the first-end cylindrical portion 60 and the second-end cylindrical portion 61, and is formed to have a predetermined length in the axial direction between the first-end cylindrical portion 60 and the second-end cylindrical portion 61. The intermediate cylindrical portion 62 has an inner surface shape along a surface shape of both end portions of the tube assembly 3 to be brazed and joined. The shape of the intermediate cylindrical portion 62 is not limited to a shape shown in FIG. 3 as long as the shape of the intermediate cylindrical portion conforms to the surface shape of both end portions of the tube assembly 3.

The tube support member 6 includes a first connector 63 that connects the first-end cylindrical portion 60 and the intermediate cylindrical portion 62. The first connector 63 is an annular plate shape portion extending in a direction intersecting with the axial direction of the tube support member 6. The first connector 63 is shaped to be inclined with respect to the intermediate cylindrical portion 62 so as to come closer to the second-end cylindrical portion 61 in the axial direction toward the intermediate cylindrical portion 62. The tube support member 6 includes a second connector 64 that connects the intermediate cylindrical portion 62 and the second-end cylindrical portion 61. The second connector 64 is an annular plate shape portion extending in a direction intersecting with the axial direction of the tube support member 6. The second connector 64 is shaped to be inclined with respect to the intermediate cylindrical portion 62 so as to come closer to the first-end cylindrical portion 60 in the axial direction toward the intermediate cylindrical portion 62.

The tube support member 6 is a cylindrical body in which the first-end cylindrical portion 60, the first connector 63, the intermediate cylindrical portion 62, the second connector 64, and the second-end cylindrical portion 61 are formed integrally with each other. The tube support member 6 can be manufactured by bending a plate-like member formed into the above-mentioned predetermined shape into an annular shape by a press machine or the like, and joining the end portions to each other. The tube support members 6 are connected to the tank 4, the tank 5, the shell body 2, and the tube assembly 3 in a state where those members are supported so as to be pressed from the outside. With the above configuration, since a force acts on the tube support member 6 from the tank 4, the tank 5, the shell body 2, and the multiple tubes 30 in the radially outward direction, a bonding force in the tube support member 6 can be secured by leveraging acting forces from each member in the same direction.

A tip portion 22 and the second-end cylindrical portion 61 of the shell body 2 are brazed and joined to each other in a state in which an inner peripheral surface of the second-end cylindrical portion 61 and an outer peripheral surface of the tip portion 22 are in contact with each other. The upstream-side open end provided inside the tip portion 22 is located on the downstream side of the second connector 64 and the intermediate cylindrical portion 62 along the exhaust gas flow in the axial direction.

The tube 30 and the tube support member 6 are brazed and joined to each other in a state in which a tip portion 300 of the tube 30 and an inner surface of the intermediate cylindrical portion 62 are in contact with each other. The brazed joint between the tube 30 and the intermediate cylindrical portion 62 is located on the second side in the axial direction and radially inward of the welded joint between the tank 4 and the first-end cylindrical portion 60. The joining of the shell body 2 and the tube support member 6 and the joining of the tube assembly 3 and the tube support member 6 can be performed by an in-furnace brazing process in which an assembly of the shell body 2, the tube support member 6, and the tube assembly 3 is heated at a melting temperature of a brazing material in the furnace.

After the in-furnace brazing process, a welding process is performed to join the tank 4 and the tank 5 to the assembly in which the contact portions of the respective members are brazed and joined to each other. Through the above welding process, a downstream-side tip portion 42 of the tank 4 and the first-end cylindrical portion 60 are welded and joined to each other in a state in which the inner peripheral surface of the first-end cylindrical portion 60 and the outer peripheral surface of the downstream-side tip portion 42 are in contact with each other. A downstream-side open end 42 a provided inside the downstream-side tip portion 42 is located upstream of the first connector 63, the intermediate cylindrical portion 62, and tip open ends 300 a of the tubes 30 along the exhaust gas flow in the axial direction. When the downstream-side tip portion 42 of the tank 4 and the first-end cylindrical portion 60 are welded together, the downstream-side open end 42 a and the tip open end 300 a are brought into an opposing positional relationship, and the internal space of the tank 4 and internal passages 30 a of the respective tubes 30 communicate with each other.

The connection between the tank 5 and the tube support member 6 is the same as the connection between the tank 4 and the tube support member 6 described above. In other words, the upstream-side tip portion 52 of the tank 5 corresponds to the downstream-side tip portion 42 of the tank 4, and an upstream-side open end 52 a of the tank 5 corresponds to the downstream-side open end 42 a of the tank 4. As a result, the upstream-side opening of the tank 5 and the tip open ends 300 a of the tubes 30 assume an opposing positional relationship, the internal space of the tank 5 and the internal passage 30 a of each tube 30 communicate with each other, and a series of exhaust gas passages in which the inside of the tank 4, the internal passage 30 a, and the inside of the tank 5 communicate with each other are configured.

The passage in the exhaust pipe is connected in order to the passage in the tank 4, the internal passage 30 a in each tube 30, the passage in the tank 5, and the passage in the pipe connected to the flange portion 51. In the EGR cooler 1, a part of the exhaust gas discharged from the engine flows down through the passage in the tank 4, the internal passage 30 a in each tube 30, and the passage in the tank 5 from the passage in the exhaust pipe in a stated order, and flows out from the outflow port 50 of the flange portion 51. The exhaust gas flowing out of the EGR cooler 1 is suctioned into the engine again.

On the other hand, the coolant water of the engine flows into the water passage 2 a in the shell body 2 from the water inflow pipe 20 and flows out of the water outflow pipe 21, while the coolant water exchanges a heat with the exhaust gas flowing through the internal passages 30 a of the tubes 30. In the EGR cooler 1, since the heat exchange is performed between the exhaust gas and the coolant water inside the shell body 2, the exhaust gas is sufficiently cooled and then suctioned into the engine. This makes it possible to contribute to the clearance of the exhaust gas regulation, an improvement in the fuel efficiency, and the like.

FIG. 4 shows a joint relationship of each part as a comparative example with respect to the heat exchanger of the first embodiment. According to the comparative example shown in FIG. 4, a tube sheet 60G has a shape extending only toward tanks 4 and 5 in an axial direction from a brazed joint with the tube 30. For that reason, the brazed joint between the shell body 2 and the tube sheet 60G is located outside the heat exchanger in the axial direction from a brazed joint between the tube 30 and the tube sheet 60G. The joint between the tube sheet 60G and the tank 4 is welded and joined to each other. In the comparative example, such a shape of the tube sheet 60G increases a dimension in the axial direction. According to the heat exchanger of the first embodiment, the problem of the comparative example can be solved and the axial length can be reduced.

In addition, according to the comparative example shown in FIG. 4, each tube 30 and the tube sheet 60G are brazed and joined to each other in a state in which the tube 30 is inserted into an opening 60G1 passing through the tube sheet 60G in a plate thickness direction. For that reason, a contact area between the tube 30 and the tube sheet 60G is small, and a sufficient brazing joint strength between the tube 30 and the tube sheet 60G cannot be obtained. Therefore, it can be assumed that the amount of heat transferred from the welded joint between the tanks 4 and 5 and the tube sheet 60G gives a large heat density per unit area of the brazed joint, and a joint strength of the brazed joint is lowered by the heat of welding.

Next, the operation and effect of the heat exchanger exemplified in the first embodiment will be described. The heat exchanger includes the tanks 4 and 5, the multiple tubes 30, the tube support member 6 joined to and supporting the multiple tubes 30 and joined to the tanks 4 and 5, and the shell body 2 accommodating the multiple tubes 30 inside and joined to the tube support member 6. The tube support member 6 is a cylindrical body extending in the alignment direction in which the tanks 4 and 5 and the shell body 2 are aligned. The tube support member 6 is formed to have the first-end cylindrical portion 60 provided on the first side in the axial direction in the cylindrical body, the second-end cylindrical portion 61 provided on the second side in the axial direction, and the intermediate cylindrical portion 62 provided with a predetermined length in the axial direction between the first-end cylindrical portion 60 and the second-end cylindrical portion 61, which is a portion smaller in diameter than the first-end cylindrical portion 60. The tanks 4 and 5 and the first-end cylindrical portion 60 are welded and joined to each other. The shell body 2 and the second-end cylindrical portion 61 are brazed and joined to each other. The outer peripheral portion of the tube 30 is brazed and joined to the inner surface of the intermediate cylindrical portion 62 in a contact state, so that the tube 30 is supported to the tube support member 6. The brazed joint between the shell body 2 and the second-end cylindrical portion 61 is located inside the brazed joint between the outer peripheral portion of the tube 30 and the intermediate cylindrical portion 62 in the axial direction.

According to the above heat exchanger, since the shell body 2 is brazed and joined to the tube support member 6 on the inner side in the axial direction, that is, on the second side of the brazed joint of the tube 30 with the intermediate cylindrical portion 62, the axial length of the heat exchanger can be reduced. The intermediate cylindrical portion 62 has a diameter smaller than that of the first-end cylindrical portion 60 welded and joined to the tanks 4 and 5. With the above configuration, a heat transfer distance between the welded joint and the brazed joint can be ensured.

According to the heat exchanger of Patent Literature 1, since the tube sheet and each tube are brazed and joined to each other in a state in which the tube is inserted into an opening penetrating through the tube sheet in the plate thickness direction, a contact area between the tube and the tube sheet is small, and thus a sufficient brazing joint strength cannot be obtained. Therefore, if the brazed joint and the welded joint of the tube and the tube sheet are not sufficiently separated from each other in terms of distance, there is a concern that the joint strength of the brazed joint is lowered by the heat generated by welding. As described above, in the heat exchanger of Patent Literature 1, there is room for improvement in securing the strength of the brazed joint between the tube and the tube sheet.

On the other hand, according to the heat exchanger of the first embodiment, the multiple tubes 30 and the tube support member 6 are brazed and joined to each other in a state in which the outer peripheral portions of the tubes 30 are brought in contact with the inner surface of the intermediate cylindrical portion 62 having a predetermined length in the axial direction. With the above configuration, since a large surface area of the brazed joint between the intermediate cylindrical portion 62 and the tube 30 can be increased, the amount of heat received per unit area of the brazed joint in the amount of heat transferred from the welded joint can be reduced. With a reduction in the amount of heat received per unit area in the brazed joint, since a thermal shock to the brazed joint can be alleviated, a damage to the brazed joint due to welding can be reduced. Therefore, a heat exchanger capable of securing the strength of the brazed joint can be obtained. In addition, even in the case of being thermally affected by thermal distortion or the like due to welding, the joint surface area between the intermediate cylindrical portion 62 and the tube 30 can be increased, so that the joining force necessary for the heat exchanger can be secured. Since the brazed joint between the shell body 2 and the second-end cylindrical portion 61 is separated from the welded joint through the intermediate cylindrical portion 62, the thermal influence of welding is further reduced, and the joint strength can be ensured. As described above, the above heat exchanger can improve a joint surface area between the tube 30 and the tube support member 6 and reduce the influence of heat from the welded joint to the brazed joint.

The intermediate cylindrical portion 62 has a diameter smaller than that of the second-end cylindrical portion 61. According to the above configuration, the heat transfer distance between the intermediate cylindrical portion 62 and the second-end cylindrical portion 61 can be ensured to be at least half of a diameter dimension difference. For that reason, the heat transfer distance from the welded joint to the brazed joint of the second-end cylindrical portion 61 can be lengthened, so that a heat exchanger can be provided in which the thermal influence of the brazed joint between the tube support member 6 and the shell body 2 from the welded joint is reduced.

The tube support member 6 includes the first connector 63 that connects the intermediate cylindrical portion 62 and the first-end cylindrical portion 60 in a plate shape extending in a direction intersecting with the axial direction, and the second connector 64 that connects the intermediate cylindrical portion 62 and the second-end cylindrical portion 61 in a plate shape extending in a direction intersecting with the axial direction. According to the above configuration, the heat transfer distance between the intermediate cylindrical portion 62 and the first-end cylindrical portion 60 includes the length of the longitudinal cross section of the first connector 63, and the heat transfer distance between the intermediate cylindrical portion 62 and the second-end cylindrical portion 61 includes the length of the longitudinal section of the second connector 64. For that reason, since the heat transfer distance from the welded joint to the brazed joint of the intermediate cylindrical portion 62 and the heat transfer distance from the welded joint to the brazed joint of the second-end cylindrical portion 61 can be lengthened, a heat exchanger can be provided in which the thermal influence of each brazed joint from the welded joint is reduced.

A heat exchanger according to a second embodiment will be described with reference to FIG. 5. Configurations, actions, and effects not specifically described in the second embodiment are the same as those in the first embodiment, and only points different from the first embodiment will be described below.

An EGR cooler 1 according to a second embodiment differs from the EGR cooler 1 of the first embodiment in a positional relationship between the shell body 2 and the second-end cylindrical portion 161. As shown in FIG. 5, a tip portion 22 of the shell body 2 and a second-end cylindrical portion 161 of a tube support member 106 are brazed and joined to each other in a state in which an outer peripheral surface of the second-end cylindrical portion 161 and an inner peripheral surface of the tip portion 22 are in contact with each other.

According to the heat exchanger of the second embodiment, as shown in FIG. 5, the tube support member 106 is coupled to the tanks 4 and 5 and the shell body 2 in a state in which the tube support member 106 is sandwiched between radially inward and radially outward. As a result, since an external force in the opposite direction acts on the tube support member 106 at both end portions, the external force does not concentrate on the tube support member 106 in one direction due to the joining between the tanks 4 and 5 and the shell body 2, so that a load can be reduced.

A heat exchanger according to a third embodiment will be described with reference to FIG. 6. Configurations, actions, and effects not specifically described in the third embodiment are the same as those in the first embodiment, and only differences from the first embodiment will be described below.

An EGR cooler 1 according to the third embodiment differs from the EGR cooler 1 of the first embodiment in the shape of a tube support member 206. As shown in FIG. 6, the tube support member 206 does not have a portion corresponding to the second connector 64 of the tube support member 6. The tube support member 206 is a cylindrical body in which a first-end cylindrical portion 60, a first connector 63, an intermediate cylindrical portion 62, and a second-end cylindrical portion 261 are integrally configured. The intermediate cylindrical portion 62 and the second-end cylindrical portion 261 are configured so as to have approximately the same diameter. The intermediate cylindrical portion 62 and the second-end cylindrical portion 261 configure a cylindrical portion having a straight line longitudinal cross-sectional shape. A tip portion 22 of a shell body 2 and the second-end cylindrical portion 261 of the tube support member 206 are brazed and joined to each other in a state in which an inner peripheral surface of the second-end cylindrical portion 261 and an outer peripheral surface of the tip portion 22 are in contact with each other.

According to the heat exchanger of the third embodiment, the tube support member 206 is coupled to the tank 4, the tank 5, the shell body 2, and a tube assembly 3 in a state of pressing and supporting those components from the outside. With the above configuration, since a force acts on the tube support member 206 from the tank 4, the tank 5, the shell body 2, and the multiple tubes 30 in the radially outward direction, the bonding force in the tube support member 206 can be ensured by leveraging the acting force in the same direction from each member.

A heat exchanger according to a fourth embodiment will be described with reference to FIG. 7. Configurations, actions, and effects not specifically described in the fourth embodiment are the same as those of the first embodiment and the third embodiment, and only differences from the first embodiment and the third embodiment will be described below.

An EGR cooler 1 according to the fourth embodiment differs from the EGR cooler 1 of the third embodiment in a positional relationship between the shell body 2 and the second-end cylindrical portion 261. As shown in FIG. 7, a tip portion 22 of the shell body 2 and a second-end cylindrical portion 261 of a tube support member 206 are brazed and joined to each other in a state in which an outer peripheral surface of the second-end cylindrical portion 261 and an inner peripheral surface of the tip portion 22 are in contact with each other.

According to the heat exchanger of the fourth embodiment, as shown in FIG. 7, the tube support member 206 is coupled to the tanks 4 and 5 and the shell body 2 in a state in which the tube support member 206 is sandwiched between radially inward and radially outward. As a result, since an external force in the opposite direction acts on the tube support member 206 at both end portions, the external force does not concentrate on the tube support member 206 in one direction due to the joining between the tanks 4 and 5 and the shell body 2, so that a load can be reduced.

A heat exchanger according to a fifth embodiment will be described with reference to FIG. 8. Configurations, actions, and effects not specifically described in the fifth embodiment are the same as those in the first embodiment, and only differences from the first embodiment will be described below.

An EGR cooler 1 according to the fifth embodiment differs from the EGR cooler 1 of the first embodiment in the shape of the tube support member 306, the end shape of the tanks 4 and 5 joined to the tube support member 306, and the end shape of the shell body 2. As shown in FIG. 8, the tube support member 306 is a cylindrical body in which a first-end cylindrical portion 360, an intermediate cylindrical portion 62, and a second-end cylindrical portion 361 are integrally configured. The tube support member 306 includes a first-end cylindrical portion 360 joined to the tanks 4 and 5 on a first side in the axial direction of the cylindrical body. The first-end cylindrical portion 360 is an annular plate portion extending in a direction intersecting with the axial direction. The first-end cylindrical portion 360 has a shape extending along a downstream-side tip portion 142 of the tank 4 and an upstream-side tip portion 152 of the tank 5 to be welded and joined. The first-end cylindrical portion 360 is an annular portion extending in a direction orthogonal to the axial direction, similarly to the downstream-side tip portion 142 and the upstream-side tip portion 152. The first-end cylindrical portion 360 is a portion having a diameter larger than that of the intermediate cylindrical portion 62.

The tube support member 306 includes, on the second side of the cylindrical body in the axial direction, the second-end cylindrical portion 361 to be joined to the shell body 2. The second-end cylindrical portion 361 is an annular plate portion extending in a direction intersecting with the axial direction. The second-end cylindrical portion 361 is shaped to extend along the tip portion 122 of the shell body 2 to be brazed and joined. The second-end cylindrical portion 361 is an annular portion extending in a direction orthogonal to the axial direction, similarly to the tip portion 122. The second-end cylindrical portion 361 is a portion having a diameter larger than that of the intermediate cylindrical portion 62.

According to the direction in which the first-end cylindrical portion 360 extends in the fifth embodiment, the heat transfer distance between the first-end cylindrical portion 360 and the intermediate cylindrical portion 62 can be secured at least half of a difference in diameter dimension between the first-end cylindrical portion 360 and the intermediate cylindrical portion 62. For that reason, since the heat transfer distance from the welded joint to the brazed joint of the intermediate cylindrical portion 62 can be increased, a heat exchanger can be provided in which the thermal influence of the brazed joint between the tube support member 306 and the tube 30 from the welded joint is reduced.

According to the direction in which the second-end cylindrical portion 361 extends in the fifth embodiment, the heat transfer distance between the second-end cylindrical portion 361 and the intermediate cylindrical portion 62 can be secured at least half of a difference in diameter dimension between the first-end cylindrical portion 360 and the intermediate cylindrical portion 62. For that reason, since the heat transfer distance from the welded joint to the brazed joint of the intermediate cylindrical portion 62 and the heat transfer distance from the welded joint to the brazed joint of the second-end cylindrical portion 361 can be lengthened, a heat exchanger can be provided in which the thermal influence of each brazed joint from the welded joint is reduced.

A heat exchanger according to a sixth embodiment will be described with reference to FIG. 9. Configurations, actions, and effects not specifically described in the sixth embodiment are the same as those in the first embodiment, and only differences from the first embodiment will be described below.

An EGR cooler 1 according to the sixth embodiment differs from the EGR cooler 1 of the first embodiment in the shape of a tube support member 406. As shown in FIG. 9, the tube support member 406 has a longitudinal cross-sectional shape in which an intermediate cylindrical portion 462 protrudes radially inward from a first-end cylindrical portion 460 and a second-end cylindrical portion 461. The tube support member 406 has a block-like longitudinal cross-sectional shape in which a radial thickness dimension is thicker than the plate thickness of each of tubes 30, tanks 4 and 5, and a shell body 2. The thickness dimension based on a difference in radial dimension between an inner peripheral surface and an outer peripheral surface of the first-end cylindrical portion 460 is larger than the thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. The thickness dimension based on a difference in radial dimension between an inner peripheral surface and an outer peripheral surface of the second-end cylindrical portion 461 is larger than the thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. It is preferable that the thickness dimension of the first-end cylindrical portion 460 and the thickness dimension of the second-end cylindrical portion 461 are twice or more of the thickness dimensions of the tubes 30, the tanks 4 and 5, and the shell body 2. The thickness dimension based on a difference in the radial dimension of the inner peripheral surface and the outer peripheral surface of the intermediate cylindrical portion 462 is larger than the thickness dimension of the first-end cylindrical portion 460 and the thickness dimension of the second-end cylindrical portion 461. The thickness dimension of the intermediate cylindrical portion 462 is preferably at least twice the thickness dimension of the first-end cylindrical portion 460 and the thickness dimension of the second-end cylindrical portion 461.

According to the sixth embodiment, the tube support member 406 has a block-like longitudinal cross-sectional shape that is thicker than the plate thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. The intermediate cylindrical portion 462 is located radially inward of the first-end cylindrical portion 460 and the second-end cylindrical portion 461. The joints of the first-end cylindrical portion 460, the intermediate cylindrical portion 462, and the second-end cylindrical portion 461 with respect to the other members are provided at intervals in the axial direction. According to the above configuration, the tube support member 406 is a cross-sectional block-shaped member having a larger heat capacity per unit length in the axial direction than that of the tubes 30, the tanks 4 and 5, and the shell body 2. According to the configuration in which the heat capacity of the tube support member 406 is large, the heat of the welded joint is hardly transmitted to the brazed joint of the intermediate cylindrical portion 462, which contributes to a reduction in the thermal influence on the brazed joint. Further, the welded joint of the first-end cylindrical portion 460 and the brazed joint of the intermediate cylindrical portion 462 are spaced apart from each other in the axial direction, thereby contributing to securing a heat transfer distance between the welded joint and the brazed joint. Also, the separation in the axial direction between the welded joint of the first-end cylindrical portion 460 and the brazed joint of the second-end cylindrical portion 461 contributes to securing the heat transfer distance between the welded joint and the brazed joint in the same manner.

The intermediate cylindrical portion 462 is an annular projection portion protruding radially inward of the tube support member 406 more than the first-end cylindrical portion 460 and the second-end cylindrical portion 461. According to the above configuration, the transfer of the heat of the welded joint to the intermediate cylindrical portion 462 is delayed, and the tube support member 406 can be coupled to the tank 4, the tank 5, the shell body 2, and the tube assembly 3 in a state of pressing and supporting those components from the outside. For that reason, since a force acts on the tube support member 406 from the tank 4, the tank 5, the shell body 2, and the multiple tubes 30 in the radially outward direction, the bonding force in the tube support member 406 can be ensured by leveraging the acting force in the same direction from each member.

Further, the radial thickness dimension of the intermediate cylindrical portion 462 is twice or more the thickness dimension of the first-end cylindrical portion 460 in the radial direction. According to the above configuration, the heat capacity in the intermediate cylindrical portion 562 can be further increased, thereby being capable of contributing to contribute to a reduction in the thermal influence on the brazed joint.

A heat exchanger according to a seventh embodiment will be described with reference to FIG. 10. Configurations, actions, and effects not specifically described in the seventh embodiment are the same as those in the first embodiment and the sixth embodiment, and only differences from the first embodiment and the sixth embodiment will be described below.

An EGR cooler 1 according to the seventh embodiment differs from the EGR cooler 1 of the sixth embodiment in the shape of a tube support member 506. As shown in FIG. 10, a tube support member 506 has a longitudinal cross-sectional shape in which a radial thickness dimension of an intermediate cylindrical portion 562 is larger than the radial thickness dimension of a first-end cylindrical portion 560 and a second-end cylindrical portion 561. The tube support member 506 has a block-like longitudinal cross-sectional shape in which a radial thickness is thicker than the plate thickness of each of tubes 30, tanks 4 and 5, and a shell body 2. The thickness dimension based on a difference in radial dimension between an inner peripheral surface and an outer peripheral surface of the first-end cylindrical portion 560 is larger than the thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. The thickness dimension based on a difference in radial dimension between an inner peripheral surface and an outer peripheral surface of the second-end cylindrical portion 561 is larger than the thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. It is preferable that the thickness dimension of the first-end cylindrical portion 560 and the thickness dimension of the second-end cylindrical portion 561 are twice or more of the thickness dimensions of the tubes 30, the tanks 4 and 5, and the shell body 2. The thickness dimension based on a difference in the radial dimension of the inner peripheral surface and the outer peripheral surface of the intermediate cylindrical portion 562 is larger than the thickness dimension of the first-end cylindrical portion 560 and the thickness dimension of the second-end cylindrical portion 561. The thickness dimension of the intermediate cylindrical portion 562 is preferably at least twice the thickness dimension of the first-end cylindrical portion 560 and the thickness dimension of the second-end cylindrical portion 561.

Each of a downstream-side tip portion 42 of the tank 4 and an upstream-side tip portion 52 of the tank 5, and the first-end cylindrical portion 560 are welded and joined to each other. The tip portion 22 of the shell body 2 and the second-end cylindrical portion 561 are brazed and joined to each other in a state in which an inner peripheral surface of the tip portion 22 and an outer peripheral surface of the second-end cylindrical portion 561 are in contact with each other.

According to the sixth embodiment, the tube support member 506 has a block-like longitudinal cross-sectional shape that is thicker than the plate thickness of each of the tubes 30, the tanks 4 and 5, and the shell body 2. The intermediate cylindrical portion 562 is located radially inward of the first-end cylindrical portion 560 and the second-end cylindrical portion 561. The joints of the first-end cylindrical portion 560, the intermediate cylindrical portion 562, and the second-end cylindrical portion 561 with respect to the other members are provided at intervals in the axial direction. According to the above configuration, the tube support member 506 is a cross-sectional block-shaped member having a larger heat capacity per unit length in the axial direction than that of the tubes 30, the tanks 4 and 5, and the shell body 2. According to the configuration in which the heat capacity of the tube support member 506 is large, the heat of the welded joint is hardly transmitted to the brazed joint of the intermediate cylindrical portion 562, which contributes to a reduction in the thermal influence on the brazed joint. Further, the welded joint of the first-end cylindrical portion 560 and the brazed joint of the intermediate cylindrical portion 562 are spaced apart from each other in the axial direction, thereby contributing to securing a heat transfer distance between the welded joint and the brazed joint. Also, the separation in the axial direction between the welded joint of the first-end cylindrical portion 560 and the brazed joint of the second-end cylindrical portion 561 contributes to securing the heat transfer distance between the welded joint and the brazed joint in the same manner.

Further, the intermediate cylindrical portion 562 is a portion of an inner peripheral surface to be brazed and joined to the outer peripheral portion of the tube 30 in a state of being in contact with the outer peripheral portion of the tube 30. The first-end cylindrical portion 560 is a portion of the outer peripheral surface which is welded and joined to the tanks 4 and 5 in a state of being in contact with the tanks 4 and 5. The second-end cylindrical portion 561 is a portion of the outer peripheral surface which is brazed and joined to the shell body 2 in a state of being in contact with the shell body 2. According to the above configuration, the radial distance between the welded joint in the first-end cylindrical portion 560 and the brazed joint in the intermediate cylindrical portion 562 can be ensured by at least the radial thickness dimension of the first-end cylindrical portion 560. This makes it difficult for the heat of the welded joint to be transmitted to the brazed joint of the intermediate cylindrical portion 562, and contributes to a reduction in the thermal influence on the brazed joint.

Further, the radial thickness dimension of the intermediate cylindrical portion 562 is twice or more the thickness dimension of the first-end cylindrical portion 560 in the radial direction. According to the above configuration, the radial distance between the welded joint in the first-end cylindrical portion 560 and the brazed joint in the intermediate cylindrical portion 562 can be further increased, thereby being capable of contributing to a reduction in the thermal influence on the brazed joint.

A heat exchanger according to an eighth embodiment will be described with reference to FIG. 11. Configurations, actions, and effects not specifically described in the eighth embodiment are the same as those in the first embodiment and the seventh embodiment, and only differences from the first embodiment and the seventh embodiment will be described below.

An EGR cooler 1 according to the eighth embodiment differs from the EGR cooler 1 of the seventh embodiment in the shape of a tube support member 606. As shown in FIG. 11, a tube support member 606 is provided with a first side groove recessed from a first side end face toward a second side, and a second side groove recessed from a second side end face toward a first side. Each of the first side groove and the second side groove is annularly provided in the tube support member 606. The downstream-side tip portion 42 of the tank 4 and the upstream-side tip portion 52 of the tank 5 are fitted into the first side groove, and the first-end cylindrical portion 660 provides the first side groove. The tip portion 22 of the shell body 2 is fitted into the second side groove, and the second-end cylindrical portion 661 provides the second side groove. The downstream-side tip portion 42 and the upstream-side tip portion 52, which are fitted in the first side groove, are welded and joined to the first-end cylindrical portion 660. The tip portion 22 fitted in the second side groove is brazed and joined to the second-end cylindrical portion 661.

According to the eighth embodiment, the intermediate cylindrical portion 662 is a portion of an inner peripheral surface to be brazed and joined to the outer peripheral portion of the tube 30 in a state of being in contact with the outer peripheral portion of the tube 30. The first-end cylindrical portion 660 is a portion that provides the groove recessed from the first side end face to the second side of the tube support member 606, and is welded and joined to the tanks 4 and 5 fitted in the groove. The second-end cylindrical portion 661 is a portion that provides the groove recessed toward the first side from the first side end face of the tube support member 606, and is brazed and joined to the shell body 2 fitted in the groove. According to the above configuration, the tube support member 606 has a heat capacity portion capable of storing a heat on both sides of radially outward and the radially inward of the welded joint in the first-end cylindrical portion 660. This makes it difficult to transfer the heat of the welded joint to the brazed joint of the intermediate cylindrical portion 662, which contributes to a reduction in the thermal influence on the brazed joint.

A heat exchanger according to a ninth embodiment will be described with reference to FIG. 12. Configurations, actions, and effects not specifically described in the ninth embodiment are the same as those in the first embodiment, and only differences from the first embodiment and the seventh embodiment will be described below.

An EGR cooler 1 according to the ninth embodiment differs from the EGR cooler 1 of the first embodiment in the shape of the tube support member 706 and the shape of the ends of the tanks 4 and 5 joined to the first-end cylindrical portion 760. As shown in FIG. 12, a tube support member 706 is a cylindrical body in which a first-end cylindrical portion 760, an intermediate cylindrical portion 762, and a second-end cylindrical portion 761 are integrally configured. The tube support member 706 includes a first-end cylindrical portion 760 joined to the tanks 4 and 5 at a first side of the cylindrical body in the axial direction. The first-end cylindrical portion 760 is an annular plate portion extending in a direction intersecting with the axial direction. The first-end cylindrical portion 760 has a shape extending along a downstream-side tip portion 142 of the tank 4 and an upstream-side tip portion 152 of the tank 5 to be welded and joined. The first-end cylindrical portion 760 is an annular portion extending in a direction orthogonal to the axial direction, similarly to the downstream-side tip portion 142 and the upstream-side tip portion 152. The first-end cylindrical portion 760 is a portion having a diameter larger than that of the intermediate cylindrical portion 762. The second-end cylindrical portion 761 corresponds to the second-end cylindrical portion 61 of the first embodiment.

The disclosure in the present specification is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and variations based on the embodiments by those skilled in the art. For example, the disclosure is not limited to the combinations of components and elements shown in the embodiments, and can be implemented with various modifications. The disclosure may be implemented in various combinations. The disclosure may have additional portions that may be added to the embodiments. The disclosure encompasses the omission of parts and elements of the embodiments. The disclosure encompasses the replacement or combination of components, elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiments.

In the embodiments described above, the first fluid is an exhaust gas and the second fluid is a coolant water, but the present disclosure is not limited to the above configurations. The first fluid may be a fluid having a temperature lower than that of the second fluid.

The heat exchanger disclosed in the embodiments described above is configured to include the tube assembly 3 in which the adjacent tubes 30 are stacked integrally with each other in a state of being in contact with each other, but the heat exchanger according to the present disclosure is not limited to the above configuration. The tube assembly 3 may have a configuration in which the adjacent tubes 30 are stacked on each other in a state of being in contact with each other at a part of the end portions or the like of the tubes 30.

In the embodiment described above, the tube 30 is formed by putting two tube plates on each other, but the present disclosure is not limited to the above configuration, and the tube 30 may be formed by an integral tube member. A cross-sectional shape of the tube 30 is not limited to a flat rectangular shape, and may be another shape such as a round shape.

While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. To the contrary, the present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various elements are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure. 

What is claimed is:
 1. A heat exchanger comprising: a tank into or from which a first fluid flows; a plurality of tubes through which the first fluid flows; a tube support member which is joined to and supports the plurality of tubes, the tube support member being joined to the tank; and a shell body which accommodates therein the plurality of tubes such that a second fluid flows around the tubes, the shell body being joined to the tube support member, wherein the tube support member is a cylindrical body extending in an alignment direction along which the tank and the shell body are aligned, the tube support member includes: a first-end cylindrical portion provided on a first end part of the cylindrical body in an axial direction, a second-end cylindrical portion provided on a second end part of the cylindrical body in the axial direction, and an intermediate cylindrical portion which is smaller in diameter than the first-end cylindrical portion and is between the first-end cylindrical portion and the second-end cylindrical portion, the intermediate cylindrical portion having a predetermined length in the axial direction, the tank and the first-end cylindrical portion are welded to each other, the shell body and the second-end cylindrical portion are brazed to each other, outer peripheral portions of the plurality of tubes are in contact with and brazed to an inner surface of the intermediate cylindrical portion such that the tube support member supports the outer peripheral portions of the plurality of tubes, and a brazed joint between the shell body and the second-end cylindrical portion is located inward in the axial direction more than brazed joints between the outer peripheral portions of the plurality of tubes and the intermediate cylindrical portion.
 2. The heat exchanger according to claim 1, wherein the plurality of tubes form a tube assembly in which the adjacent tubes are in contact with and stacked integrally on each other, and the outer peripheral portions of the tube assembly are in contact with and brazed to the inner surface of the intermediate cylindrical portion such that the tube support member supports the outer peripheral portions of the tube assembly.
 3. The heat exchanger according to claim 1, wherein the intermediate cylindrical portion is smaller in diameter than the second-end cylindrical portion.
 4. The heat exchanger according to claim 3, wherein the tube support member includes: a first connector which is an annular plate portion extending in a direction intersecting with the axial direction and connects the intermediate cylindrical portion and the first-end cylindrical portion; and a second connector which is an annular plate portion extending in the direction intersecting with the axial direction and connects the intermediate cylindrical portion and the second-end cylindrical portion.
 5. The heat exchanger according to claim 1, wherein the first-end cylindrical portion is an annular plate portion extending in a direction intersecting with the axial direction and being welded to the tank.
 6. The heat exchanger according to claim 5, wherein the second-end cylindrical portion is an annular plate portion extending in a direction intersecting with the axial direction and being brazed to the shell body.
 7. The heat exchanger according to claim 1, wherein the tube support member has a block shape and is larger in thickness in longitudinal cross-section than the plurality of tubes, the tank, and the shell body, the intermediate cylindrical portion is located radially inward of the first-end cylindrical portion and the second-end cylindrical portion, and the respective joints in the first-end cylindrical portion, the intermediate cylindrical portion, and the second-end cylindrical portion are spaced apart from each other in the axial direction.
 8. The heat exchanger according to claim 7, wherein the intermediate cylindrical portion is an annular projection portion protruding radially inward of the tube support member more than the first-end cylindrical portion and the second-end cylindrical portion.
 9. The heat exchanger according to claim 7, wherein the intermediate cylindrical portion has an inner peripheral surface of the tube support member which is in contact with and brazed to the outer peripheral portions of the plurality of tubes, the first-end cylindrical portion has an outer peripheral surface of the tube support member which is in contact with and welded to the tank, and the second-end cylindrical portion has an outer peripheral surface of the tube support member which is in contact with and brazed to the shell body.
 10. The heat exchanger according to claim 8, wherein a thickness of the intermediate cylindrical portion in a radial direction of the tube support member is twice or more of a thickness of the first-end cylindrical portion in the radial direction.
 11. The heat exchanger according to claim 7, wherein the intermediate cylindrical portion has an inner peripheral surface which is in contact with and brazed to the outer peripheral portions of the plurality of tubes, the first-end cylindrical portion has a groove recessed from an end face of the first end part of the tube support member toward the second end part such that the tank is fitted to the groove and welded to the first-end cylindrical portion, and the second-end cylindrical portion has a groove recessed from an end face of the second end part of the tube support member toward the first end part such that the shell body is fitted to the groove and brazed to the second-end cylindrical portion. 